   (-meta [coll] meta)
 
   ISeq
-  (-first [coll] (-first front))
+  (-first [coll] (first front))
   (-rest  [coll]
     (if-let [f1 (next front)]
       (PersistentQueueSeq. meta f1 rear nil)


  ICollection
  (-conj [coll o]
    (PersistentHashSet. meta (-assoc hash-map o nil) nil))

  IEmptyableCollection
  (-empty [coll] (with-meta cljs.core.PersistentHashSet/EMPTY meta))

  IEmptyableCollection
  (-empty [_] nil)

  IIndexed
  (-nth
   ([_ n] nil)
   ([_ n not-found] not-found))

  INext
  (-next [_] nil)

